5" exhaust question

[Bovee]

I just purchased a 2007. 5 6. 7L 3500 dullie. . I am doing some research to see what exhaust i want. . my old truck was a 1998. 5 24v and i had banks 4" exhaust on that. . i am thinking about 5" exhaust on the new one but i want to see if any one has 5" on there 6. 7L and if you have any pro and con's about it. . i had my 1998. 5 for 8 years so now i have to learn the ropes about the new 6. 7L... any help would be wonderfull... i am looking to do the dual exhaust out each corner... I think that looks tough on a dullie truck. give me your input. thanks

 

[Bovee]

also whats the word on the filter delete kits???trouble??worth it??

 

[Cosmo]

If you have emissions testing, filter deletes are a pain. If you don't have to worry about it, then they're a godsend.

IMHO 5" is overkill on a mostly stock truck.

 

[Bovee]

Im in alaska and ''supposedly'' they are eliminating the emission testing in april... which will be awesome... plus they don't do much on the diesels up here as far as testing. I think the 5" probably will be overkill for where my truck is at this point. . maybe down the road... I am looking for an exhaust that has a little more throat to it than my banks system did. . But i also don't want it annoying me at high way speeds. .

 

[Jim W]

I am using a 5" TBE with a 6" tip from MBRP, on a 08,6. 7L Mega Cab. My truck does not have the deep throaty sound that you are looking for. My son has a 06, 5. 9L with the same exhaust set-up, his does have the deep throaty sound.



I believe that the VGT with the exhaust brake effects the sound from the exhaust system, thus there is no throaty sound. In fact when I engage the exhaust brake at high idle my truck sounds like a jet engine with a high pitch whine. His turbo is the stock unit from a 5. 9L with no exhaust brake attached and his truck does have the deep throaty sound.



When you put the two trucks next to each other and have the engine running anyone who knows diesel engines and a Cummins can pick-out the 6. 7L every time. Even my wife knows the difference between the two sounds of the different trucks.



One nice feature I do have is when it is summer time and the kids have the rap music pump up in their cars I can drown them out at the stop light. I just engage the exhaust brake and put the truck in neutral with the high idle engage, then the jet engine appears.

Jim

 

[Harlacher]

Is the 5" any harder to get parts for like an exhaust brake? I have a four inch and thought about 5 but at the time there was not much support for it.

 

[Bovee]

would you go with the 5" if you were to do it again?

 

[Jim W]

Is the 5" any harder to get parts for like an exhaust brake? I have a four inch and thought about 5 but at the time there was not much support for it.

I am not sure since I have on 08, with the 6. 7L engine that has the stock VGT with the factory exhaust brake installed. I do know that the transition point from the Turbo exhaust port which is 4" will mate to the 5" exhaust with no issues. The first part of the down tube has a 4" collar and transition to the 5" pipe at this point. So you use the factory exhaust clamp here to fasten the exhaust pipe. The rest of the 5" TBE will mate up to the factory sport brackets and you use the factory rubber supports to secure it.

Jim

 

[Jim W]

would you go with the 5" if you were to do it again?

Yes, I would. I am just saying the sound is different than the 5. 9L engine with the stock turbo on the 5. 9L.



Jim

 

[Jeremiah]

If you like the different sound or more noise, go for it. If you're looking for more power, fergit it. Larger, open or "straight" pipes don't make much difference at all unless you're developing upwards of 500 hp or more. Waste of money.

 

[KeithTaylor]

If you like the different sound or more noise, go for it. If you're looking for more power, fergit it. Larger, open or "straight" pipes don't make much difference at all unless you're developing upwards of 500 hp or more. Waste of money.

I have wondered about this exact issue myself - my truck is all stock right now, but am thinking of adding a Smarty Jr and 50HP injectors to make a little more power for towing. I would like a little more exhaust note, but don't want to spend $400. 00 for something that won't make a difference in the horsepower/torque.

KD

 

[Jeremiah]

Hi, Keith, Robert Patton has written about this a number of times in the TDR. He's has to be circumspect so he doesn't pound on advertisers too much, but he is honest with the members and the message is clear that larger exhausts don't do much until you generate upwards of 500 hp or more. But if you're running a Smarty and injectors too, you might be getting on up there yourself. Check it out with Robert, Joe Donnelly or some of the other folks who write for the TDR. They'll give you the straight scoop. Think of it this way: to get more power you need, among other things, more air in and more air out. If you're not pulling in bigger chunks of air, there won't be a need to force more air out. The Smarty can change the timing and you can add bigger injectors (which means more fuel is being burned), but it's the turbos that pull the air in. Without more or bigger turbos, you won't have more air going in. Now that's a layman's unscientific explanation of what goes on and I'm already in over my head, so if Joe or Robert or any of the other writers want to straighten out what I just said, feel free to jump in.

 

[KeithTaylor]

Thanks Jeremiah, I think you are on the right track with your comments - sounds like an exhaust won't be needed unless I add a bigger turbo, etc. I use this truck for pulling an 11K lb. trailer, so I don't want to mess up the reliability by adding too much power. I appreciate the advice . . .

KD